Junction field effect transistor structures, for example, as described in U.S. Pat. No. 6,251,716, U.S. Pat. No. 6,307,223, U.S. Pat. No. 6,255,513, and U.S. Pat. No. 6,486,011, have advantages over bipolar transistors. These advantages include lower on-resistance, lower noise margin, higher ESD protection and faster switching speed.